The Royal Navy with CVA01

[uk 75]

If the Royal Navy had ordered the CVA01 as planned and it had entered.service in the early 1970s it would have changed the shape of the fleet substantially.
Of the remaining aircraft carriers, only Hermes was modern enough to serve without refit.
It was planned that Eagle would be the other Phantom equipped carrier. But both she and Ark Royal were in poor condition and would probably have been sacrificed to keep CVA01.
Just as Ark Royal served alone from 1972 to 1979 CVA01 would have had to do the same.
Hermes would still have been needed in the Commando role.
Assuming CVA01 had entered service by 1974, the Conservative and Labour governments might have wanted to keep the workforce together and order CVA02 for delivery at the turn of the decade.
A real CVA01 is likely to have lost Seadart and the big Kojak radar, though not necessarily. The Type 82 Bristol might have trialed both systems (the Dutch Tromp entered service at about the same time).
It was intended to build four T82 to escort CVA01. If this had gone ahead, the County class is likely to have been withdrawn faster.
It would still have been necessary to replace the Leanders with suitable ships. But they might have been closer to the Leander than the T21 T22 and T42.
The Tiger class conversions might also have had to be sacrificed to find resources for CVA01. New homes for their Seakings were available on Commando ships, RFA and CVA01.
So by 1981 we have a surface fleet of 1 CVA01 1 Commando ship 4 T82 4 County and a mixture of some 32 frigates. About the same as we actually had but with the escorts less capable than those in otl ( no Exocet, fewer Seadart ships, and a less sophisticated T22 equivalent replacing the Leanders.
CVA01 and Polaris might also have slowed down work on the SSN force.

 

[Archibald]

The big question is, how good a carrier would have CVA-01 been ? What kind of capability ? upgraded Midway, Forrestal, Kitty Hawk or Kennedy ?

My vague rememberances of "Navy matters - CVA-01" long gone early Internet website are of an absolute botched, compromised horror ship.

Any chance it could have resulted in a decent ship down the line ?

Might have been interesting for France in the 80's, even if not (sacro sanct) nuclear as per CdG.
With a little luck, it will drag the Clems successors well above 50 000 tons and thus out of reach of the boomers K15 reactors... and if the French Navy has to create carrier reactors from scratch, maybe it will run away from the costs, and go with something akin to PA.2 / CVF / whatever.

Because, as far as CdG goes, they reused K15 reactors from the 2nd generation, preaet day boomers - just to try and make some economies.
Conveniently forgetting a) two of them at 80 000 hp would be less powerful than a Clem' machinery at 130 000 hp and b) boomers = marathon, carriers = Ussain Bolt.

 

[uk 75]

It is a big leap to get CVA01 ordered in 1966 as planned.
NATO would have been delighted to have her for the Striking Fleet, but the UK was also a leader in ASW at a time when the Soviet subs were the main threat in the North Atlantic.
However, if the RN had based its carrier doctrine on NATO rather than East of Suez there is an outside chance CVA01 could have been built.
As I wrote above, she would have been simpler than the version we know. Radar fit closer to an Invincible and probably no Seadart ( hence Bristol plus three get built as Task Force escorts).
A steam boiler powered ship would probably have slowed down the drive to a gas turbine fleet. But UK was pretty good at fudging so a mixed powerplant might have emerged.
The airgroup was planned to be the same as Ark Royal. As long as CVA02 gets built it would be possible to have one and sometimes 2 available as France did with Clem and Foch.
The snags are all too clear. The RN reckoned it needed at least three carriers to ensure it needs were met.
Retaining Eagle and Hermes (as the strike carrier with Bucs only) would have required too.much money and crews for not so much return.
Hindsight after a decade (nearly) of operating Ark shows us that CVA01 could have done the job alone though 02 would have made all the difference
The RN was not very good at building big ships postwar and most had problems getting into service. CVA01 could have been a horrendous white elephant and been cancelled or scrapped at any of the financial crunch points from 1966 to 1982.
On balance I have come to the view that the RN did rather better by focussing on ASW assets like the Invincibles. T22 and SSN from Healey to Nott. But the schoolboy in me hankers after CVA01.
Way back when I was 11 or so my local library had the 1963/4 edition of Jane's Fighting Ships (already several years old and passed on from the main Oxford Library). At the back was an artist's impression of what I later learnt was CVA01. The fighters are the VG fighter/strikers envisaged in OR346 rather than F4s.

 

[CV12Hornet]

A real CVA01 is likely to have lost Seadart and the big Kojak radar, though not necessarily. The Type 82 Bristol might have trialed both systems (the Dutch Tromp entered service at about the same time).

I think it very likely that it loses both systems on cost grounds - electronics are the most expensive part of any ship, and removing the Kojak radar in particular would likely save the RN a pretty penny.

It was intended to build four T82 to escort CVA01. If this had gone ahead, the County class is likely to have been withdrawn faster.
It would still have been necessary to replace the Leanders with suitable ships. But they might have been closer to the Leander than the T21 T22 and T42.

Cracking open Friedman's book on British postwar frigates and destroyers, the final escort mix was intended to be six Type 82s, 30 anti-submarine frigates, and 45 corvettes. The ASW frigates converged around a 4400-ton design with a gun, Ikara, and a single Sea Wolf, designated Type 17; the corvette evolved into a light 2600-ton frigate intended for peacetime sea control and in wartime as a sonar sensor node, and would have had a light helicopter, gun, and Sea Cat launcher.

This corresponds surprisingly well to the Type 21 and 22 frigates, and shows their origins in the carrier-fleet thinking. While final numbers would almost certainly be cut I do think it likely the Royal Navy proceeds with these two designs, though they'd want to get the Type 17 manning levels down closer to the Type 22's.

The Tiger class conversions might also have had to be sacrificed to find resources for CVA01. New homes for their Seakings were available on Commando ships, RFA and CVA01.

Very likely. The conversion program was already on shaky ground by 1965; CVA-01 and the associated costs would be a straightforward nail to pound in their coffin.

 

[zen]

It's a tricky one on Sea Dart, the military argument for it was strong. But strictly Sea Wolf would be more important.

Again this is where a certain overlap with other AH elements smooths the path. Had ASWRE C-band been funded instead of the Dutch Broomstick. Then it actually permits a reduction in Sea Dart system costs.....and an easier installation. As well as more ships equipped.

Had facilities to develop higher power plant, shafts and props allowed a reduction to twin sets instead of triple, the released volume allows a reduction in the ship for a given level of capability and at less cost.

Had the CV been designed around a maximum individual aircraft weight of 60,000lb and catapults of 225ft.
The whole thing could be reduced in size/weight/cost.
That 42,000ton study starts to look attractive.

Had F4K come in closer to predicted cost instead of being nearly three times that.....

Had F8U-III won instead of F4, it might further alter the landscape here.

Insert enough minor changes and they build up to CVA-01 would likely go ahead.

 

[CV12Hornet]

Had facilities to develop higher power plant, shafts and props allowed a reduction to twin sets instead of triple, the released volume allows a reduction in the ship for a given level of capability and at less cost.

Shafts and props, sure. Power plant... ehhhhh. I read a paper a while back on marine propulsion and it noted that marine gas turbine development depends on aero gas turbine development, simply because the costs of gas turbine development are so high, and the marine unit numbers so much smaller, that it's simply not economical to design a bespoke marine gas turbine rather than adapting an aero engine for the task.

Which leads to the problem that there isn't a British jet engine available for the task more powerful than the Olympus. The more powerful LM2500 and MT30 gas turbines are based on the CF6 and Trent engines, respectively, and those were engine classes the UK just didn't have available in the 1960s. There was the RB211 - but that engine's development was horribly marred and its prospects for marinization correspondingly low.

 

[uk 75]

The illustration I posted above with its twin Seadart launchers aft gives a clue as to what the RN wanted in its CVA. As the initials also make clear we are talking a British version of the Kennedy class.
Similarly the aircraft had to be the same fighter as the USN, nothing less would do. An upgraded Buccaneer was also planned.
No wonder that it was already eyeing up F111B
It is easy to see this as vainglorious posturing. But the maiñ role of CVA01 was to keep the UK's position as Flag of one of the two striking groups in NATO's Striking Fleet. In its East of Suez role the RN had cast envious eyes on US carriers since the Korean War.
Such was the respect the US had for British carrier aviation that it was willing to let the UK have two Essex class ships to keep it alive.
The 1966 Fleet Working Party reflects US input on ASW instead. The US found it hard to replace its own CVS ASW carriers with new ships. Italy's helicopter cruisers showed what might be done.
There is thus no place for the 1957 40000 ton carrier or the Centaurs in the RN carrier force for the 60s and 70s.
It is all too easy to work back from the 1982 Falklands War and try and produce two better ships than Hermes and Invincible. Such an expeditionary role featured not at all in the RN's priorities except as an adjunct to NATO and East of Suez roles.
Ark Royal's complicated story from 1966 to 1979 underlines my points. She represented the best capanility that the RN could squeeze out of the system.
Similarly the three Invincibles evolved to carry Amraam/Sea Eagle equipped Sea Harriers and EH101Merlins. These would have been the best CVS in NATO had the Soviet Union not collapsed.
Two CVA01s might have worked out no more expensive than the Ark and Invincibles. They would have still been in service in 1991 like Foch and Clemenceau.
The F4s and Buccaneers might have given way to the UK version, Sea Volley or Broadside, of the elegant Rafale M.
Thatcher and Mitterrand might even have agreed to build full blown nuclear replacements.

 

[Dilandu]

The big question is, how good a carrier would have CVA-01 been ? What kind of capability ? upgraded Midway, Forrestal, Kitty Hawk or Kennedy ?

Close to French "Fosh"-class, I think.

 

[zen]

Had facilities to develop higher power plant, shafts and props allowed a reduction to twin sets instead of triple, the released volume allows a reduction in the ship for a given level of capability and at less cost.

Shafts and props, sure. Power plant... ehhhhh. I read a paper a while back on marine propulsion and it noted that marine gas turbine development depends on aero gas turbine development, simply because the costs of gas turbine development are so high, and the marine unit numbers so much smaller, that it's simply not economical to design a bespoke marine gas turbine rather than adapting an aero engine for the task.

Which leads to the problem that there isn't a British jet engine available for the task more powerful than the Olympus. The more powerful LM2500 and MT30 gas turbines are based on the CF6 and Trent engines, respectively, and those were engine classes the UK just didn't have available in the 1960s. There was the RB211 - but that engine's development was horribly marred and its prospects for marinization correspondingly low.

No the Steam Plant and machinery.
UK testing infrastructure was limited to 50,000shp. This the Y300 of the 1952 and Medium Fleet Carrier studies and new high pressure system for CVA-01. Were all limited to 45,000shp-50,000shp.


What was needed was a setup over 60,000shp and ideally 70,000shp.

 

[Archibald]

The big question is, how good a carrier would have CVA-01 been ? What kind of capability ? upgraded Midway, Forrestal, Kitty Hawk or Kennedy ?

Close to French "Fosh"-class, I think.

I thought CVA01 was much more than 35000 tons... don't tell me they would do no better than Clems 40% smaller ??!!

 

[Archibald]

They would have still been in service in 1991 like Foch and Clem

They lasted a bit less than 40 years in service, 1959 - 1999.
Aplied to CVA01: 1970 - 2010 ?

 

[EwenS]

Setting aside the politics surrounding CVA-01 for a moment (difficult I know!), we need to remember that the eventual design in 1966 was the product of a design process that had begun in 1960 and that had built on the work from the 1950s. That had on more than one occasion considered ships from Foch sized (c31,000 tons) to Forrestal sized (c76,000 tons). And in that process they took account of what the U.K. could likely afford and what industry could build.

What came out of that was a ship was 53,000 tons (action condition, 54,500 tons deep) 890ft WL, 925ft OA (963ft with the bridle catcher), Hull beam 122ft, beam max 231ft, flight deck 189ft, draught 32ft.

So yes, 60,000-70,000shp machinery plant might have been nice but it was just not possible. QE2 plant was only 55,000shp per unit. So no point whinging about that. Move on.

But there is no denying the ship was to have been innovative. For example:-
Parallel deck layout that generated advantages for aircraft landing in bad weather in comparison with the then traditional angled deck.
Scissors lift (replicated in the Invincibles but with a few teething problems leading to “drunken” lift incidents)
Alaskan Highway to allow aircraft movements outboard of the island.
Access from the hangar deck to the quarterdeck to allow testing of aircraft engines without disrupting flight deck operations.
New water spray arrester gear.
There are probably others.

And it would have had advantages over existing carriers:-
Much more deck space (50% more than Eagle)
Ability to operate aircraft up to 70,000lb static load (45,000lb in the modernised Eagle)
Longer 250ft (Eagle and Ark longest was 199ft) more powerful catapults capable of launching fully loaded F4K without reheat and Buccaneer S2, with minimal wind over the deck. And without putting so much stress into the airframes.
Bigger airgroup. 36 F4K/Buccaneer. 4 AEW. 5 AS & 2 SAR helicopters (Ark as refitted 1970 26 F4K/Buccaneer. 4 AEW. 6 Sea King ASW and 2 Wessex SAR helicopters). Two thirds could be stowed in the hangar and there was deck parking for two thirds. That would allow a surge capacity of 48 F4K/Buccaneer in an emergency.
Much greater electrical generating capacity 18MW (Eagle as modernised 8.25MW. Hermes 1959 5.44MW. Victorious 5 MW)
2,140 tons of Avcat (c1,900 tons in Ark) enough for 3 days of flying ops. 6,200 tons fuel for ship (5,500 tons in Ark with less efficient machinery).

On the negative side. Well just what was RN thinking about defence of the carrier group? The escort cruiser was still being pursued in this timeframe but CVA-01 was being designed to carry both ASW helicopters and defensive weapons just like the Type 82 frigate escorts.

The CF-299/Sea Dart system was to use an entirely different magazine and loading system. Surely that alone makes it a target for cost cutting? Why not produce a standardised system able to be fitted in all types of ship?

And why fit Ikara when the whole idea was to have Ikara armed escorts?

The timescale was probably impossible to meet. Key points:-
Design ready - Jan 1966 achieved.
Tender period - Jan-Jun 1966. I’ll come back to this
Order - end of Sept 1966
Lay down - Sept 1967
Launch -Sept 1969
Acceptance - June 1972
Fully operational June 1973

There were problems finding someone / consortium to build it. Enquiries in 1965 revealed H&W Belfast had the yard capacity to build it but could not lay it down for 12 months beyond the required date. Otherwise the option was to be consortia of Clyde or Tyne yards but at least one, Fairfield, was in financial difficulties. So there were problems even getting a single bid let alone running a competition. In Jan 1966 the builder’s negotiator said they would “give it a go”. Hardly encouraging! Cancellation came in Feb with the tender documents prepared and boxed up waiting to go out.

Whichever yard(s) were chosen infrastructure upgrades would have been required simply to deal with the sheer size of the ship. And a retraining of welders to work with the specialist QT35 steel never previously used in a surface warship (it had not long been introduced for nuclear submarine construction). While initially thought onerous it was found it could be achieved in a couple of weeks but something that yards needed to plan for and cost in.

And of course there is the question of the electronic fit. Hobbs states that the fall back radar would have most likely been a transistorised version of Type 984.

There was a detailed article published in “Warship 2014” by Ian Sturton titled CVA-01: Portrait of a Missing Link” that delves into the detail of the design. And Hobbs in “The British Carrier Strike Fleet After 1945 has a good chapter about the ship and the politics.

 

[Archibald]

Very interesting. So I'd say: 1973 - 2013, just in time to be replaced by the Q.E

 

[zen]

So yes, 60,000-70,000shp machinery plant might have been nice but it was just not possible. QE2 plant was only 55,000shp per unit. So no point whinging about that. Move on.

No need for that tone!
And no need for falsehoods.
Volume efficiency favours installation that delivers the desired power for the minimum volume.
60-70,000shp was achieved by the US...at the time..because they had facilities able to test upto that level (and beyond).
Facts are not 'winging', and alter those conditions and the output differs also.

UK did not and did not invest in such. They couldn't go beyond 50,000shp so settled for 45,000shp and took the hit in volume/weight, consoling themselves that at least 3 shafts and props delivered a modicum of redundancy.

You are right that the process had begun much earlier and tradeoff studies drove a given size for a given capability level.
Actually it was eased in the mid 50's from earlier over the performance achievable with N/A.39, then F.177 and expected Sea Vixen successor (Type 556).
But hampered by the need to fit DLI, ASW, AEW, Strike and FAW into the ship.
Even as '57 came around voices were adamant that the SAM didn't obviate the need for DLI.
Longer CAP and a much wider distribution of Area Defence SAMs was the only solution to this 'religious' doctrine.
And this is what permeates CVA-01 and the carrier fleet. Which still needed a ILWS to last ditch defend attendant ships. Hence PT.428, Sea Mauler and Sea Wolf.

Agreed for then projected future airwing, the design had to be future proofed, and trends then pointed to bigger, heavier and higher TO&L speeds....that WITH the arrival of ICs from Texas Instruments.

Agreed it seems inevitable that Sea Dart System would essentially be a destroyer set instead of a separate magazine system.

 

[starviking]

The CF-299/Sea Dart system was to use an entirely different magazine and loading system. Surely that alone makes it a target for cost cutting? Why not produce a standardised system able to be fitted in all types of ship?
<SNIP>
There was a detailed article published in “Warship 2014” by Ian Sturton titled CVA-01: Portrait of a Missing Link” that delves into the detail of the design. And Hobbs in “The British Carrier Strike Fleet After 1945 has a good chapter about the ship and the politics.

I’ve only seen mention of the ‘different’ CVA-01 Sea Dart system in Hobbs’ British Aircraft Carriers, and to be honest the description sounds like a Heath Robinson contraption.

Comparing the CVA-01 plans in Sturton’s Warship 2014 article with the Sea Dart plan and description in Marland’s Post-War Weapons in the Royal Navy in Warship 2015 shows normal Sea Dart having a good fit.

Marland shows the box-shaped Sea Dart magazine, and describes the indexing system that allows missiles to be moved from a choice of lanes. I wonder if a misapprehension of how the Sea Dart magazine operates is the genesis of Hobbs’s idea of a “traveling box loader”.

 

[zen]

Might also relate to the earlier Launchers on each side, and transport from magazine to each...?

 

[JFC Fuller]

The final CVA01 design was to use the then standard (e.g. the one used on Bristol) Sea Dart system, the intention to use a specially designed carrier version was dropped following the adoption of the parallel deck and Alaskan highway, probably sometime after December 1962. After this point only a single launcher was included in the design (DGD had initially wanted 4). The Ikara launcher was removed from the design at around the same time.

My theory is that the original flight deck layout pushed the two launchers, positioned on either beam aft, to the edge of the hull so they were not directly above the magazine. Therefore, they had to be loaded horizontally (rather than vertically as Sea Dart usually is) so apparatus was required to turn the vertically stored Sea Darts horizontal prior to loading, resulting in the bespoke launcher. Rebuilding the Royal Navy has diagrams of the two flight decks and it is hard to imagine how Sea Dart could be loaded vertically on the pre-December 1962 version due to the lack of hull depth under the launchers.

 

[EwenS]

So yes, 60,000-70,000shp machinery plant might have been nice but it was just not possible. QE2 plant was only 55,000shp per unit. So no point whinging about that. Move on.

No need for that tone!
And no need for falsehoods.
Volume efficiency favours installation that delivers the desired power for the minimum volume.
60-70,000shp was achieved by the US...at the time..because they had facilities able to test upto that level (and beyond).
Facts are not 'winging', and alter those conditions and the output differs also.

UK did not and did not invest in such. They couldn't go beyond 50,000shp so settled for 45,000shp and took the hit in volume/weight, consoling themselves that at least 3 shafts and props delivered a modicum of redundancy.

You are right that the process had begun much earlier and tradeoff studies drove a given size for a given capability level.

I’m sorry if the tone offends you but the lack of investment argument offends me, fact though it is. For there to be investment there has to be either a very large purse to fund it or a marketplace with a demand needing satisfied to allow industry a return on its investment.

There was no large purse from the U.K. Govt to pay for such development in the postwar period. That is the reality of postwar Britain. Fact.

And where is the market? The need only begins to arise from 1943 with the advent of plans for large ships like the Malta class (although it made do with 50,000shp per unit). The only large postwar ships demanding such power plants in the naval market were carriers.

And what was the prospect? All the plans in the 1950s came to nothing. They couldn’t even decide on the size of ship they wanted. So when do you invest? 4 later reduced to 3 ships planned in the early 1960s with a demand of a max of 6-8 of these high powered units (2 per ship) and a high risk of that being reduced even further. How much extra cost would development of a more powerful plant have added to a project that was already subject to a great deal of scrutiny? And how long to the projected build time?

And in the civilian market there doesn’t seem to be any demand beyond the SS United States. QE2 (70,000 tons) as I mentioned was 55,000shp per unit. SS France (66,000 tons) was 40,000shp per unit. The largest ship ever built the Seawise Giant a ULCC supertanker of 646,000 tons, was powered by a single unit of 50,000shp when built in 1979. Tankers only broke the 100,000 ton mark in 1958.

As for the US, well it had those deep pockets. But it was only with the Iowa class from 1938 that it had the need to move over 50,000shp. What is interesting was that it moved to 70,000shp with the USS United States in 1947/48. Since then the output of the turbine units has remained fairly constant through 4 Forrestals, 3 Kitty Hawk and JFK before moving to nuclear generation of the steam for 10 Nimitz (reduced to 65,000shp per unit). So much greater payback on the investment.

So I have no problem with the decision around the power plant of CVA-01.

 

[zen]

Try not mistake what could ease a process along with "having issues". It's a simple analysis.
You are right that the US invested in development of higher power plant machinery for capital ships before WWII.
Much as they invested in drydock facilities.
And in each case reaped a reward later on that told in the design of carriers.

UK did not, and so was hampered by such facts when the later need arose.

So another easing tweak is simply drydocks being a little bit longer and wider. They don't even need to be supercarrier sized. But such easing of restrictions makes the process easier. More wiggle room.

Again some of this could have been forseen as early as 1919 if not earlier with Capital ship designs. But the decision ended up as one of trying to constrain by treaty.....which ultimately failed.

I rather fail to grasp how it offends one, that previous generations could make a series of minor errors that they could not forsee the compound consequences of.
Saddened perhaps.
Frustrated possibly.
Sometimes annoyed especially when it seems clear from what one can read in certain quarters at the time.
But offended?

 

[JohnR]

Sorry not familiar with the term DLI??

 

[Siberia]

Similarly the aircraft had to be the same fighter as the USN, nothing less would do.

Would the size of the ship have meant they could manage with regular F-4s and not needed the Spey re-engined variants?

An upgraded Buccaneer was also planned.

Was this an upgrade of just the electronics, or was something much more drastic like some of our timeline's later proposals planned?

Sorry not familiar with the term DLI??

At a guess deck-launched intercept, different from the US Navy's combat air patrol (CAP).

 

[zen]

Sorry not familiar with the term DLI??

Deck Launched Intercept

 

[zen]

Would the size of the ship have meant they could manage with regular F-4s and not needed the Spey re-engined variants?

Yes but at the UK specific systems would still be needed.

Was this an upgrade of just the electronics, or was something much more drastic like some of our timeline's later proposals planned?

Mostly avionics.

 

[CV12Hornet]

No the Steam Plant and machinery.
UK testing infrastructure was limited to 50,000shp. This the Y300 of the 1952 and Medium Fleet Carrier studies and new high pressure system for CVA-01. Were all limited to 45,000shp-50,000shp.


What was needed was a setup over 60,000shp and ideally 70,000shp.

That makes more sense, yes.

On the negative side. Well just what was RN thinking about defence of the carrier group? The escort cruiser was still being pursued in this timeframe but CVA-01 was being designed to carry both ASW helicopters and defensive weapons just like the Type 82 frigate escorts.

The Type 82s were initially divided into three buckets: pickets, inner-ring escorts, and defense of the amphibious force. Three Type 82s would be dedicated to the amphibious force; five was considered the minimum for picket duty in a two-carrier task force configuration (the pickets carried Sea Dart for self-defense, being posted 100 nm from the carriers and acting mostly to direct deck-launched intercepts in absence of a US-style continuous CAP); and six divided between the two carriers as the outer ring of defenses. The carrier and cruiser-launched Sea Darts, then, were the inner-ring defenses, a role filled in the US Navy by the Tartar destroyers.

As far as the escort cruiser, that was envisaged to, in addition to its carrier-defense role, be used extensively in independent operations where a carrier could not be spared. This could be in ASW work, or in small helicopter assaults - roles the French and Italians budgeted for their executions of the concept.

Of course, as both the Type 82 and escort cruiser programs were progressively cut, the carrier-based Sea Darts grew more and more important to cover the air defense shortfalls.

 

[uk 75]

The Escort Cruiser is not really necessary once you have Sea Kings based on the carrier. In addition RFA and the Commando Ship carry them too.
The four later Countys were assigned to the Commando Ship LPD and LST amphib force.
The T82 was a better way of getting Seadart and Ikara than having separate ships. Four were to be ordered initially.
Replacing the 26 Leanders would probably still have been done by T22 with T21 replacing other frigates.
I doubt the Invincibles would have been built if CVA01 had gone ahead.
The T42s and Leander Ikara conversions seem to me unnecessary too if you keep T82.
Exocet also might not have been bought given CVA01's Buccaneers and T82 Seadart surface capability.

 

[uk 75]

By 1991 the CVA01 and possibly CVA02 would have been well established in the Royal Navy.
Like the three Invincibles they would have been involved in the post Cold War military interventions.
It is unlikely that the Major government would have ordered replacements. They were too keen on the "peace dividend".
Assuming 1997 had seen the new Blair Government had come to the same conclusions in its Strategic Defence Review that it did in reality replacements for CVA01 would have followed.
But with no years of Sea Harrier operations behind it the RN would have wanted a conventional aircraft carrier like CVA01.
Might the Blair Government have bitten the nuclear bullet at last. France needed a second carrier to join De Gaulle
Could CVF have emerged as a CVN for Britain and France?
After years of working with McDD and then Boeing BAe would have wanted the F18/HarrierII successor. But without a VSTOL aircraft for the RAF or RN its relationship with Lockheed Martin might have been minimal on F35.

 

[zen]

Collaboration between MN and RN would likely never be interrupted if CVA-01 goes ahead. AN would be training with FAA a lot and BS mk6 catapults and DX2 arrestor gear might well have been ordered for the French CVN.....

And yes this alters the landscape for next generation aircraft. Anglo-French collaboration is much more likely. Possibly leaving the Germans with licensing Hornet or F15.

 

[NOMISYRRUC]

Had facilities to develop higher power plant, shafts and props allowed a reduction to twin sets instead of triple, the released volume allows a reduction in the ship for a given level of capability and at less cost. [See FWIW 3]

Shafts and props, sure. Power plant... ehhhhh. I read a paper a while back on marine propulsion and it noted that marine gas turbine development depends on aero gas turbine development, simply because the costs of gas turbine development are so high, and the marine unit numbers so much smaller, that it's simply not economical to design a bespoke marine gas turbine rather than adapting an aero engine for the task.

Which leads to the problem that there isn't a British jet engine available for the task more powerful than the Olympus. The more powerful LM2500 and MT30 gas turbines are based on the CF6 and Trent engines, respectively, and those were engine classes the UK just didn't have available in the 1960s. There was the RB211 - but that engine's development was horribly marred and its prospects for marinization correspondingly low. [See FWIW 1]

No the Steam Plant and machinery.
UK testing infrastructure was limited to 50,000shp. This the Y300 of the 1952 and Medium Fleet Carrier studies and new high pressure system for CVA-01. Were all limited to 45,000shp-50,000shp.

What was needed was a setup over 60,000shp and ideally 70,000shp. [See FWIW 2]

This is a quote from Page 41 of Modern Combat Ships 2 "Invincible" class by Paul Beaver (Ian Allan, 1984).

The machinery chosen was the proven Rolls Royce Olympus engine which powers the Concorde supersonic passenger transport. In its TM3B form the Olympus develops 28,000 shaft horsepower (shp) and is coupled in pairs in the twin shafts of the ship, through a David Brown reversible gearbox. [See FWIW 1]. The order for the Olympus power was made in 1969, although at that time the design concept of the warship was still as a through-deck cruiser rather than as an aircraft carrier. This resulted in a new approach to machinery space design; mainly because of the amount of power being generated, a conventional controllable pitch propeller would need to be specially designed, and therefore a fixed-pitch propeller was substituted. The final solution was the RN's largest propeller ever, although there were initial problems with the design causing vibration at the stern end of the ship, causing vibration at the stern end of the ship, causing at least one propeller to be changed during acceptance trials. Even today there is an appreciable amount of shudder generated at certain revolutions.

The next paragraph says...

Because of the scale of the engineering work required to produce the gas turbine engine layout in the class, Rolls-Royce built a shore test bed to represent the port-side shaft, with it's two Olympus engines. [See FWIW 2]. The total combination was of the engine, reversing gearbox, intakes, exhausts, a low-speed dynamometer and a complete set of ship's engine controls. Never before had a complete side of a ship's machinery been recreated ashore. The experiment proved especially successful during sea trials and later, during passage to the South Atlantic, where Invincible had engine problems which resulted in a complete change of one Olympus, the experience built up by Rolls-Royce proved of great experience in mid-ocean. Of course, complex and high technology does mean that more high-skilled technical leading rates are required than is necessary in steam turbine ships, but the advantages of far out-weigh the disadvantages.

FWIW 1 to @CV12Hornet

If Paul Beaver was correct that's 56,000shp on each shaft.

When I first read your post I thought you meant that the UK couldn't produce a gas turbine capable of producing 45,000shp (which is what each of CVA.01's three steam turbines would have produced) but Invincible's designers circumvented that problem by having two Olympus engines providing the power for each shaft. Which, incidentally, has the advantage that if one of the two engines fails 25% of the total shp is lost instead of 50% with a singe engine that produced double the shp.

Now I think that you mean that the UK couldn't develop a gas turbine capable of producing 60-70,000shp in the 1960s. I agree, but is one necessary? Could more powerful versions of Olympus be produced?

• 28,000shp to 30,000shp looks feasible for two engines producing a total of 60,000shp coupled to a single shaft.
• 28,000shp to 35,000shp for two engines producing a total of 70,000shp coupled to a single shaft may be too big a stretch. Does anyone know if Marine Olympus engines that powerful were considered?
• Would three Olympus engines driving one shaft be feasible? If it is three TM3B Olympus engines have a combined output of 84,000shp.

FWIW 2 to @zen

Admittedly this was at least half-a-decade after CVA.01 was designed and it's a gas rather than a steam turbine, but it does show that a "setup" over 60,000shp and ideally 70,000shp as a "one off" could have been created.

FWIW 3 to @zen

I think that 3 shafts was the correct decision.

IIRC from reading Norman Friedman's British Carrier Aviation one of the reasons why the three-shaft arrangement was chosen over four shafts because it afforded better anti-torpedo protection. That is the ship could be divided into three compartments instead of two. A two-shaft ship would also be divided into two compartments.

I can't remember what he said the advantages of three compartments over two compartments. However, I think it would limit flooding to a third of the ship instead of half. That might mean that the ship was less likely to sink before damage control measures could be taken. It would also meant that only the a third of the ship would have to be counter-flooded to maintain stability instead of half, leaving the centre compartment "dry". If one set of machinery was knocked out there's a one-third loss of power instead of half. If counter flooding of the machinery spaces on the other side of the ship is required the other half of power is lost with a two-shaft ship, but with a three-shaft ship it "only" results in the loss of another third of the ship's power, because the centre-shaft is still working. Limiting the damage to a smaller area of the ship might also make permanent repairs quicker and cheaper.

Two sets of machinery may be cheaper to build than three and they may also be cheaper to operate. I simply don't know. However, how great is the saving as a percentage of the total building and operating costs of the ship? That is: hull; machinery; electronics; and armament, which includes the aircraft as well as the weapons fitted to the ship. The overall saving may not be worth it.

And is a smaller ship that good idea? Size is important when it comes to aircraft carriers. If a reduction from three shafts to two did release volume allowing a reduction in the ship for a given capability and at less cost, does that mean a shorter catapults, shorter & narrower flight decks and shorter & narrower and hangars? I'd prefer using the reduction to produce a ship with a greater capability at the same cost.

 

[NOMISYRRUC]

Re the discussion about CVA.01s Sea Dart system... Was the system fitted to the Invincible class the same as the one fitted to the Type 42 or the Type 82? Or was it a third design, specifically designed for the class?

 

[zen]

On 3 shafts. Yes it provides greater redundancy with obvious military benefits.

However in principle.
A slight scaling up of plant machinery to permit 2 sets to achieve the output of 3. Results in less volume taken up by the installation.
This allows the designer more scope to achieve other things in the hull. Such as increased compartmentalisation, increased torpedo protection for a given beam of hull, magazines, fuel bunkers, etc....

Now the chief debate in a carrier design the RN faced was in the constraints of extent drydocks, how to achieve the capability desired.
In this the issue of deck edge lifts verses a full gallery deck dominates.
The 1960 comparison tradeoff studies show three basic options.
1. Achieve both, forcing beam to 120ft at the waterline. This restricts drydocks to one, Davenport No.10
This However restricted hanger height to 17.5ft to 18ft, and three sets of plant machinery made torpedo protection and compartmentalisation a harder task.

2. Choose between deck edge lifts OR a full gallery deck. Choose between increased internal volume for offices, cabins, storage etc...or increased hanger space and ease of aircraft movement.

In this careful note of ship heights (there bring two options in saud studies) shows a beneficial side effect of choosing edge lifts is a higher hanger height. Potentially 23ft. This means any flight deck systems underneath can still leave a working height of 17.5ft.

In essence the working in of desired features is an easier task if the volume taken by machinery is kept down.

A slightly smaller CV is easier to pass through the perceptive eye of the Treasury Needle.

 

[zen]

Re the discussion about CVA.01s Sea Dart system... Was the system fitted to the Invincible class the same as the one fitted to the Type 42 or the Type 82? Or was it a third design, specifically designed for the class?

I vaguely reccal only in the ADAWS being more comprehensive, needing more computing power.

 

[zen]

If Paul Beaver was correct that's 56,000shp on each shaft.

If this is correct, the question is where and when did such a facility to test such machinery come about?

 

[NOMISYRRUC]

If Paul Beaver was correct that's 56,000shp on each shaft.

If this is correct, the question is where and when did such a facility to test such machinery come about?

When was about half-a-decade after CVA.01 was designed.

The first paragraph that I quoted from Paul Beavers book said.

The order for the Olympus power was made in 1969, although at that time the design concept of the warship was still as a through-deck cruiser rather than as an aircraft carrier.

From Page 14 of Paul Beaver's Book.

​

Although the above table says May 1978 for the first-of-class trials the first paragraph on Page 14 says that Invincible commenced Contractor's Sea Trials in the Irish Sea and Clyde Approaches in April 1979 and that she was accepted into the RN at Portsmouth on 19th March 1980. It also says that the building contract was authorised on 17th April 1973.

Where, I don't know. This is the second paragraph that I quoted again.

Because of the scale of the engineering work required to produce the gas turbine engine layout in the class, Rolls-Royce built a shore test bed to represent the port-side shaft, with it's two Olympus engines. [See FWIW 2]. The total combination was of the engine, reversing gearbox, intakes, exhausts, a low-speed dynamometer and a complete set of ship's engine controls. Never before had a complete side of a ship's machinery been recreated ashore. The experiment proved especially successful during sea trials and later, during passage to the South Atlantic, where Invincible had engine problems which resulted in a complete change of one Olympus, the experience built up by Rolls-Royce proved of great experience in mid-ocean. Of course, complex and high technology does mean that more high-skilled technical leading rates are required than is necessary in steam turbine ships, but the advantages of far out-weigh the disadvantages.

My guess is that it was at one of Rolls-Royce's factories. Maybe the one that built the Olympus gas turbines.

 

[A Tentative Fleet Plan]

On 3 shafts. Yes it provides greater redundancy with obvious military benefits.

However in principle.
A slight scaling up of plant machinery to permit 2 sets to achieve the output of 3. Results in less volume taken up by the installation.
This allows the designer more scope to achieve other things in the hull. Such as increased compartmentalisation, increased torpedo protection for a given beam of hull, magazines, fuel bunkers, etc....

Now the chief debate in a carrier design the RN faced was in the constraints of extent drydocks, how to achieve the capability desired.
In this the issue of deck edge lifts verses a full gallery deck dominates.
The 1960 comparison tradeoff studies show three basic options.
1. Achieve both, forcing beam to 120ft at the waterline. This restricts drydocks to one, Davenport No.10
This However restricted hanger height to 17.5ft to 18ft, and three sets of plant machinery made torpedo protection and compartmentalisation a harder task.

2. Choose between deck edge lifts OR a full gallery deck. Choose between increased internal volume for offices, cabins, storage etc...or increased hanger space and ease of aircraft movement.

In this careful note of ship heights (there bring two options in saud studies) shows a beneficial side effect of choosing edge lifts is a higher hanger height. Potentially 23ft. This means any flight deck systems underneath can still leave a working height of 17.5ft.

In essence the working in of desired features is an easier task if the volume taken by machinery is kept down.

A slightly smaller CV is easier to pass through the perceptive eye of the Treasury Needle.

A smaller CV is not going to be all that much cheaper than the 53,000/54,500 ton design for CVA-01 that was drawn up. Indeed it suffers from the same problems as CVA-01, which was already displacement-constrained due to mistaken beliefs about the direct link between size and cost, and so to hold down displacement, a significant amount of novel (and risky) technological developments (including scissor-lifts, extensive use of QT-35 steel, a new rudder design etc) were incorporated into the design.

One of the reasons why the 3-shaft 53,000 ton design was selected over a competing 4-shaft 55,000 ton design was that the machinery spaces of the 53,000 ton design were in three compartment whilst the 55,000 ton design had only two compartments for machinery, rendering it more vulnerable to underwater damage.

It's worth pointing out that CVA-01's underwater protection as originally designed was as wide as that of the US super carriers, built prior to CVA-67, but had the inner foam compartments of CVA-67 (which in CVA-67s case enabled a narrower underwater protection system).

CVA-01 as shown in Warship 2014 is going to be more or less going to be what enters service possibly with the exception of some austerity-induced deletions like Sea Dart of Type 988/SPS-01, given that the design was mostly complete and they were on the cusp of sending out tenders.

A transistorised Type 984 seems to me to be a bad idea, it will be a novel system not used anywhere else in the fleet, requiring a significant amount of work to developed. Type 988/SPS-01 at least has the benefit of being used on the Type 82, Tromps and possibly any Escort Cruiser, whilst Type 965 is obsolete, but was at least fairly widely used.

 

[Hood]

The Sea Dart magazine looks to be identical to Type 82 (a 38x missile mag).
The launcher however was different to that in T82 and T42.

This crude Shipbucket-scale comparison shows the differences. The CVA-01 launcher was not as tall as that of T82s launcher, presumably to lessen chances of being hit given it was near the end of the flightdeck, and had a different base section. Had she been completed its very possible a T42 launcher would have been used, assuming T42 was still brought (which seems more likely than continued T82 production).



The 1963-64 provision of Ikara had a completely different magazine layout to other RN ships too.

EwenS' point about shipyard capacity and ability is important I think and very often overlooked. It took the best part of a decade for Vickers to prep and build HMS Invincible and there no reason to think that CVA-01 would not have been delayed post-1973.
It also places a big question mark over CVA-02 had the class not been cancelled, its possible CVA-01 would have gone to a Clyde consortium and perhaps 02 to H&W but it shows that there was no much wriggle room and there would have been skilled labour shortages in other areas of the industry which may well have impacted on T42 and frigate construction.

The mention of "drunken lift" troubles in the Invincibles makes me wonder if the scissor lift teething problems might have been worse in CVA given they would be handling much heavier loads.

The transistorised Type 984 (possibly provisionally designated Type 985 by some accounts) feels a bit mythical to me given how fleeting mentions have cropped up over the years. I'm not sure anyone in 1968-73 would bother with the effort trying to redesign an early 1950s radar for transistors. My suspicion is that they would just chuck a Type 965M mattress on it and then a 1022 sometime in the late 70s/early 80s.

 

[zen]

It's correct to say that CVA-01 was being limited in displacement by a old fashioned standing assumption that displacement = cost.

As I said and frankly as was pointed out at the time. Getting a series of 53,000ton carriers past the Treasury and Cabinet was going to be a much taller order than the average displacement of the fleet as then in discussion.

In context however the tradeoff studies result in varying capability/capacity verses cost obviously dictated by size/displacement. Those results would differ in lower end studies which would be based around twin rather than triple propulsion sets.

In essence these smaller CVs deliver slightly more capability/capacity verses cost, as does the whole range. Making them slightly more attractive in trying to pass over the hurdle of otherwise 'ignorant' political opinion.

Considering other trends It's not clear the Dutch Broomstick would actually make it onto the the CVA-01. ASWRE won funding for a research C-band array radar and this may have been more fully funded considering it relieves other pressures on the ADAWS installation.

But it's even more likely that the need to provide a future AEW system would shift focus to that goal away from 3d radar. Even if it's procurement of a US sourced solution.

 

[NOMISYRRUC]

The timescale was probably impossible to meet. Key points:-
Design ready - Jan 1966 achieved.
Tender period - Jan-Jun 1966. I’ll come back to this
Order - end of Sept 1966
Lay down - Sept 1967
Launch -Sept 1969
Acceptance - June 1972
Fully operational June 1973

The above timetable shows that the ship was to be built in 4¾ years, which is the time allowed between laying down and acceptance.

In view of the time overruns of other ships built for the Royal Navy in the 1970s completing CVA.01 on schedule would have been a miracle.

If I recall correctly from early to mid 1970s editions of Jane's Fighting Ships Invincible (laid down in 1973) was expected to take 4-5 years to built and completed in 1977-78. The second ship would take 4 years to build and be completed in 1980. The third ship would take 3-4 years to build and be completed in 1981 or 1982. However, I think it also expected the second and third ships to be ordered and laid down earlier than they eventually were.

However, Invincible (laid down July 1973 and completed in March 1980) took 6½ years (80 months) to build. The building time for Illustrious (laid down October 1976 and completed in June 1982) was 5½ years (68 months) and Ark Royal (laid down December 1978 and completed in July 1985) took about 6½ years (79 months) to build. The average building time for the class was 76 months or about 6¼ years.

The entries on the Type 21 frigate in editions of Jane's Fighting Ships from around 1970 say that the Amazon (laid down in November 1969) was to be completed in May 1972, which is a building time of 2½ years (30 months), but she was actually competed in May 1974 which is a building time of 4½ years (54 months). I think that by the mid-1970s editions they were saying that all 8 ships would be delivered by the end of 1977, but Avenger wasn't completed until May 1978. The ship built in the shortest length of time was Ardent at 40 months (3⅓ years) and the longest building time was Active at 71 months (nearly 6 years). The average building time for the class was 50 months (about 4¼ years).

Similarly, they say that Sheffield, the first Type 42 (laid down in January 1970) was to be completed in July 1973, but she was actually completed in February 1975. So instead of being built in 3½ years (42 months) she was actually built in just over 5 years (61 months). They also say that the 6 Batch 1 ships were to have been completed by the end of 1977. However, the only other ship to be completed by that date was Birmingham which was completed in December 1976, 4¾ (57 months) after she was laid down. The 6th ship to be completed was Cardiff in December 1979, nearly 7 years (83 months) after she was laid down. The average building time for the six Batch 1 ships was 5½ years (66 months). However, IIRC Friedman said the delay wasn't the fault of the shipyards, it was the fault of the manufacturers of the electronic equipment concentrating on their export contracts.

The building times for the Type 42 Batch 2 and 3 ships weren't much better. The average for the four Batch 2 ships was 4½ years (55 months) and the average for the four Batch 3 ships at nearly 5½ years (64 months) was only slightly shorter than the building time for the six Batch 1 ships.

*** *** ***​

Though, to be fair to the British naval armaments industry, the situation wasn't any better on the other side of the pond.

For example... My copy of Jane's Fighting Ships 1968-69 says that Nimitz (laid down July 1968) was to be completed 1971-72 which would be a building time of 3-4 years.

That was in line with the earlier super carriers. Enterprise (laid down in February 1958 and competed in November 1961) was built in just over 3¾ years (46 months) and the average building time for the first 9 super carriers was 3¾ years (44 months).

However, Nimitz wasn't completed until May 1975 which was nearly 7 years (82 months) after she was laid down.

Eisenhower was even worse. She was laid down in August 1970 and completed in October 1977 over 7 years (86 months) later.

This had a knock-on effect upon Carl Vinson. According to Jane's Fighting Ships 1968-69 she should have been ordered in FY1971, but wasn't ordered until FY1974. The ship was laid down on 11th October 1975 (the day Eisenhower was launched) and completed in March 1982 for a building time of 6½ years (77 months).

So instead of the first 3 Nimitz class being built in 3-4 years and joining the fleet between 1972 and 1976 they were built in an average of 6¾ years (82 months) and joined the fleet between 1975 and 1982.

IIRC editions of Jane's from the middle 1970s attributed the delays to Nimitz and Eisenhower to labour difficulties at the shipyards and reactor components being delivered 2 years late.

 

[NOMISYRRUC]

Re the discussion on the transitorised Type 984.

I remember reading somewhere that Hermes and Victorious had the standard Type 984 radar, but that Eagle had the Type 984M. If I remember the RN radar designation system properly the "M" meant Mk 2.

If that isn't a case of false memory syndrome might the Type 984M have been the transistorised version?

Hermes and Victorious had the CDS which in Eagle was replaced by ADA which used three Ferranti Poseidon computers, which I'm guessing used transistors and early integrated circuits instead of valves.

 

[NOMISYRRUC]

The transistorised Type 984 (possibly provisionally designated Type 985 by some accounts) feels a bit mythical to me given how fleeting mentions have cropped up over the years. I'm not sure anyone in 1968-73 would bother with the effort trying to redesign an early 1950s radar for transistors. My suspicion is that they would just chuck a Type 965M mattress on it and then a 1022 sometime in the late 70s/early 80s.

For what it's worth the Type 42 Batch 1 destroyers were fitted with the Type 965P and that's probably what CVA.01 would have had until Type 1022 became available. (I think "P" was the equivalent of Mk 3 in the RN's radar designation system with "Q" being the equivalent of Mk 4.)

My source for that is Page 58 of Modern Combat Ships 3 - Type 42 by Leo Marriott (Ian Allan, 1985) which also says that the Type 965 fitted to these ships was an updated variant using solid-state circuitry.

Later on he wrote that the Type 1022 was developed from the Dutch LW-08 radar and was intended to be an interim replacement for the 965 until the long term replacement (Type 1030) became available.

 

[EwenS]

The mention of "drunken lift" troubles in the Invincibles makes me wonder if the scissor lift teething problems might have been worse in CVA given they would be handling much heavier loads.

Only the forward lift was a scissors lift. Report here about the problems experienced by them through to the mid 1980s.

https://attachment.tapatalk-cdn.com/15085/202112/717275_2bc0789cd7fdd32ac0ec9a412616bd66.doc?Expires=1652457123&Signature=PV8RycX6pmG-ENACHTbQNftnGYYXoovuU4lRdpQXHdqcOErcRl3tBLXYX2pCnbWnYrqJJRffuQlU1ceJqX92CcHdmWwOqD5sPJzCKy-8I-rfGJj45hATq53~KaDTnNtTmtB9Q~lLDLTotK9pbg~67nFeHRTZY6y2wihFu67FYiRFBY1ccovWNWU2l9yyJNAvO2oR0eswkJBmIdXUt5~HVJdhFbwl98fVt4Q2ab5IEwq909~UaCV~Yer91ImkQ5vrmhEC6QuesyJnw2opPbD65HYLZoP6WqayM4A6o4trya3rk4e6nbKCdBSP079CyjSwNLinjYD~hK~A0DuxMaPAuw__&Key-Pair-Id=APKAJS72YROXJYGYDADA

Major lift failure:-